The Variety Of Microbial Community In Biogas Digesters And Analysis On Methanoarchaea Community Structure

To know more details about microbial community in biogas digesters, especially the structure and variety of methanoarchaea community, could provide microbial parameters for better designing of the process of biogas fermentation. MPN(most probable number) technique, T-A cloning and DGGE(denaturing gradient gel electrophoresis) methods were applied to study the variety of microbial community and methanoarchaea community structure in biogas digesters in this article.There are 9.5×107 cells/ml and 2.5×106 cells/ml fermentative bacteria in each normal digesters. Cellulytic anaerobic bacteria are 9.5×10 cells/ml, mehanoarchaea are 4.5×106 cells/ml and 2.5×107 cells/ml, Sulfate reducing bacteria are 4.5×105 cells/ml and 1.5×105 cells/ml. The bacteria and methanoarchaea libraries were constructed separately. Through the public databases (GenBank) blasted. To bacteria, the dominant cluster is uncultured bacteria, others are clostridiales, syntrophus and gamma proteobacterium. Some of 16S rDNA sequences similarities are low (<95%). To methanoarchaea, methanocorpusculum is dominant, the following are methanoculleus, methanosaeta, methanospirillum and methanosarcina mazei. The microbial diversity and variety can be tracked by using PCR-denaturing gradient gel electrophoresis(DGGE) in different digesters, simultaneously dynamic change in normal one. The results showed: compared to methanoarchaea, the bacteria microbial community displayed more complex. In startup period, the dominant bacteria are gamma proteobacterium and bacillus. Eubacterium is dominant during producing CH4 normally and later time. Bacteroidetes is dominant in another normal digester suited elsewhere. To methanoarchaea, Methanocorpusculum is the only dominant archaea in the biogas digesters suited in Shuangliu experimental station. But in another place, the dominant clusters are methanoculleus and methanosaeta.Bacteria in biogas has more diversity than methanoarchaea.